Again, this is NOT happening anytime in the near future and why you won't find it on Bruce's site. Bruce / Ocean Planet Energy are the marine market distributors for Firefly..

Yes Firefly clearly developed a brochure, and may even have some prototypes in the lab, but they are doing all they can just to keep up with the G31 12V and everything else is on the back burner.

I had lunch with Bruce and the Firefly inventor, the guy who's name is on the patent, just yesterday so am not guessing on this. No 6V and no 4V in the foreseeable future and the 12V will be in limited supply.

If anyone is interested in Firefly's, I know Bruce just got a few in, but I have no idea when he will get more. Price from OPE is $425.00 each, plus shipping.

We can actually get them again now, after being backlogged much of the summer. Usually shipping in batches of 12ea, last PO took just a couple weeks to mfg, ship, and arrive. At the moment we have stock in Maine, NorCal (LTD Marine), SoCal (RCC Marine) and Seattle (BRJ Solutions). We are looking for a FL distributor to step up and stock them. Once we get enough on the ground here & there then the occasional backlogs won't matter as much.

__________________
Twice around was enough for me...
Now I just help others prep for ocean trips...www.bruceschwab.com

E.g. assuming a daily 100Ah net usage, 100A (actual steady charge) charger for a 200Ah AGMbattery, how many minutes would it take to efficiently replace the 100Ah of usable energy? A regular AGM could take .5C (or the whole 100A) for about 24min. If the battery were 100% efficient in recharge, then that would be 24/60x100A=40Ah, at which point the battery goes in to absorption charging so it will take less and less charge per minute. But you still need to take the regular AGM up to 100% again (or close to) otherwise you pay a very steep cycle life penalty. I.e. you can't just size up the bank so you only have to replace up to the 80% SOC, although you would get some additional cycle life by only going down to 67% SOC daily. You should be able to roughly figure out the daily engine run time required.

If the charger is an enginealternator, the motor is still burning (roughly) close to the same amount of fuel per minute as it was for the 100A full alt ouput but only putting in less and less of the amps. Fuel, noise, heat, engine wear and tear, etc. costs associated with that.

If I am understanding all this right, the LFP would be the winner in that it would not have any decrease in charge rate from 30% to 80% SOC so the run time would be dramatically shorter, and never has to get to 100%. Theoretically then the engine would only have to run for an hour using the same alternator. The CF would be second because it can start at 30% and take high bulk amps for longer than the regular tech AGM. It still only needs to get to 80% SOC most all the time (weekly or less often to 100%?). But it still will drop off from bulk to absorption charging at some point like any AGM, only it will be in bulk for more of the time, resulting in some additional time to get to 80% SOC. Some estimate of this could be made. The regular AGM needs to go from 50% (where it is closer to pushing back on the charge rate than the others) to 100% as much as possible - with a dramatic loss in cycle life if not done daily or thereabouts. So it would take X amount of engine run time over and above what the CF battery would need. You could go with a bigger AGM bank but there is no free lunch and you'll still need to run longer..

exMaggieDrum

I'm not the expert that Mainesail is, so he may well counter-dict everything that I'm going to say.

But from my limited experience with both types of battery chemistry, if you are wanting the absolute fastest max charge, LiFePo is your only option. What makes CF-AGM desirable, for at least me, is that it is the only Pb based chemistry that can deal with multiple partial charges without any capacity loss. After a week or two on the hook, I can go back to the marina and plug in. And while I'm away (for sometimes months) the CF-AGM will be allowed to fully charge and return to their original capacity.

Also, and I've said this in previous posts, LiFePo's don't like to remain at 100% SoC. So to assure that I have full batts's, I need to devise a complicated charging/discharging scheme to occur while I'm away from the boat.
This is no big deal for the small boat which is only 100 miles away. But the big boat is over a 1000 miles away. In an event of an emergency, I'm many, many hours away.
Hence the reason CF-AGM's are looking very, very good to me. At least for the big boat.

But I realize that my kind of sailing is vastly different than others. More dock time than hook time. So what I'm saying may be totally irrelevant to your situation.

....
Also, and I've said this in previous posts, LiFePo's don't like to remain at 100% SoC. So to assure that I have full batts's, I need to devise a complicated charging/discharging scheme to occur while I'm away from the boat. ....

A lot of people, myself included, have a small cheap LA bat. to use while at the dock;
I try to get the LiFePo4 to 50% and then switch to the LA when docking for extended periods.

I'm not the expert that Mainesail is, so he may well counter-dict everything that I'm going to say.

But from my limited experience with both types of battery chemistry, if you are wanting the absolute fastest max charge, LiFePo is your only option. What makes CF-AGM desirable, for at least me, is that it is the only Pb based chemistry that can deal with multiple partial charges without any capacity loss. After a week or two on the hook, I can go back to the marina and plug in. And while I'm away (for sometimes months) the CF-AGM will be allowed to fully charge and return to their original capacity.

Also, and I've said this in previous posts, LiFePo's don't like to remain at 100% SoC. So to assure that I have full batts's, I need to devise a complicated charging/discharging scheme to occur while I'm away from the boat.
This is no big deal for the small boat which is only 100 miles away. But the big boat is over a 1000 miles away. In an event of an emergency, I'm many, many hours away.
Hence the reason CF-AGM's are looking very, very good to me. At least for the big boat.

But I realize that my kind of sailing is vastly different than others. More dock time than hook time. So what I'm saying may be totally irrelevant to your situation.

Thanks for your thoughts. I am coming to the same conclusion as to the LFP batts. There are trade-offs for both (surprise, surprise). I live less than 2 miles from my boat but there will be times (I hope) in the future where I have to leave the boat somewhere and go away for some time. So that is a factor. I think I could live with having a low PSOC on the LFPs though since I have a large DC genset that could bring the batteries up pretty fast. I would always want enough to handle bilge pumps if needed though. But any battery will run out in that scenario given enough time.

This is not an easy decision. Something else I have to consider is resale of my boat if that becomes necessary. I hope it doesn't for at least the next five years but things happen. I think it would be a lot easier selling a boat with AGMs (which just happen to be CF) that look like normal batteries and wouldn't freak out any potential buyer, let alone a surveyor. The LFPs would be scarier to most I think, especially since they would look radically different and certainly would have to be handled in a much more complicated way.

I need some digest time though. I'm an analytical type so I am going to make some lists and a spreadsheet (or something) to put everything done in one spot that addresses all the different battery management issues, pluses, and minuses. I'm then going to review the programming I can do with my inverter/charger, my alternator regulator, and my solar controller. As part of that I'm going to sketch out the installation diagrams for each. E.g. it looks like it would be best to have a separate DC positive load bus from a charger sources bus for the LFP system, along with solenoid enabled switches to turn them on or off. Also have to figure out how to handle the start battery and keeping it charged with both scenarios.

May be I am making too much of this, but in the end, may be I will actually learn some of the details and make a good decision. Right now I am a little in shock that I am seriously considering going to either CF or LFP right now.

I got a nice reply to my inquiry on pricing and availability of the Firefly G31s from Brian at BRJ Marine in Seattle. The batteries are $425 (same as Ocean reported above) plus an inbound shipping/handling fee of $25-$35 (picked up at his facility in Seattle). And he has batteries in stock, although I did not specify a quantity.

He also forwarded me the manual for the battery. A good start with this vendor.

I think it would be a lot easier selling a boat with AGMs (which just happen to be CF) that look like normal batteries and wouldn't freak out any potential buyer, let alone a surveyor. The LFPs would be scarier to most I think, especially since they would look radically different and certainly would have to be handled in a much more complicated way.

I can speak from experience on the resale issue.
As our smaller boat is for sale, the broker has suggested that we swap out the LiFePo's for a more "Normal" (his words) system. He has told me that several folks have shy'd away from my boat because of them. Although there are other reasons...same or less money can buy a larger boat here, but the batteries are just another reason to look at other boats.

I can speak from experience on the resale issue.
As our smaller boat is for sale, the broker has suggested that we swap out the LiFePo's for a more "Normal" (his words) system. He has told me that several folks have shy'd away from my boat because of them. Although there are other reasons...same or less money can buy a larger boat here, but the batteries are just another reason to look at other boats.

I would not sell our boat with the LFP bank I would bring it with me to the next boat... I designed it so the system could easily be converted back to lead in about 3-4 hours work...

I would not sell our boat with the LFP bank I would bring it with me to the next boat... I designed it so the system could easily be converted back to lead in about 3-4 hours work...

Yeah...
Thought about that, but the small boat only has two charging sources. AC charger and alt.. The large boat has both them, plus solar and wind. All of the sources have older controllers which don't play well with LiFePo. Meaning they all have to be replaced. Beings the bigger boat currently have AGM's, all of the current chargers can be use with only minor programming changes for the CF-AGM's.

Change the small boat's over is no big deal. Just remove the cells, BMS, solenoids ...etc. Install some buss jumpers and AGM batt's. Set the controller back to factory settings and we're good to go.
As you said, 3 to 4 hours of work. Even have some folks who want the LiFePo's.

But that is the whole reason I started this thread. I wanted to make sure that I really wanted to go the CF-AGM route.
Unless some earth shattering revelation comes up, I see CF-AGM's in my future.

I would not sell our boat with the LFP bank I would bring it with me to the next boat... I designed it so the system could easily be converted back to lead in about 3-4 hours work...

Good plan. And, the old boat would sell even easier with new batts. Works so long as you get a new boat that can use and handle the old LFPs. If I sell, I probably won't get another. But by then the tech may be more accepted and I could sell it to some one else that is ready for it (like MissouriSailor).

I just checked again on the prices for the packaged LFP batts and BMS from OceanPlanet. All I can say is Wow! Feel very comfortable with OP though as a vendor and knowledge on the subject though. But if it is LFP I would have to go with a DIY - hopefully well-thought out, workable, and reliable. Seems definitely doable with the EV equipment available now. Things can change before that though, e.g. prices come down on the CFs so I can afford a bigger bank, or prices change on the LFPs, or more options.